‘Christmas star’: Jupiter, Saturn to align on December 21 for the first time in 800 years

In a historical event occurring after nearly 800 years, Jupiter and Saturn will align closest in the night sky on December 21 forming the ‘Christmas Star’ in a phenomenon called the ‘great conjunction’. According to NASA, the two planets will appear the brightest in the sky as they converge closer in their respective orbits. “The vibrant planetary conjunction will be easily visible in the evening sky over the next two weeks as the bright planets Jupiter and Saturn come together,” NASA informed in a release. 

While the planetary alignment is not an uncommon phenomenon in the solar system, the two celestial bodies Jupiter and Saturn align only once in 20 years. The 2020 spectacle is, however, rare as these two planets will be at their ‘closest point’ triggering the brightest light like the Star of Bethlehem some 2000 years ago. Sky-gazers will be able to watch the alignment with the naked eye in the southwest of the sky just after the sunset.

According to NASA, even as the two planets appear to merge in the sky from the Earth, they are actually hundreds of millions of miles apart in space. This is also caused partially due to the earth’s axis tilt during the winter solstice that will make the two planets look closer than they actually are. 

“Conjunctions like this could happen on any day of the year, depending on where the planets are in their orbits,” said Henry Throop, an astronomer in the Planetary Science Division at NASA Headquarters in Washington. “The date of the conjunction is determined by the positions of Jupiter, Saturn, and the Earth in their paths around the Sun, while the date of the solstice is determined by the tilt of Earth’s axis.

The solstice is the longest night of the year, so this rare coincidence will give people a great chance to go outside and see the solar system,” he added. Furthermore, Troop said that night skywatchers will be able to be to see Jupiter on the inside lane, approaching Saturn all month and finally overtaking it on December 21.

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How to watch the event:

• On can get away from the city lights and find an unobstructed view of the sky, such as in an open field. Jupiter and Saturn, according to NASA, are intensely bright and one must be able to look in the sky and have a clear view nearly from anywhere. 
• Viewers are advised to look for the two planets at least an hour after sunset and are advised to look to the southwestern sky. NASA explains, “Saturn will be slightly fainter and will appear slightly above and to the left of Jupiter until December 21, when Jupiter will overtake it and they will reverse positions in the sky.”
• One can see the two planets with the human naked eye but if binoculars or a small telescope is used, viewers can see the four large moons orbiting Jupiter. 

[Jupiter and Saturn. Credit: twitter/@PenPure1]

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